Field of the Invention
The invention relates to a method for COB mounting of electronic chips on a circuit board by contact connection of connecting wires and substantially whole-area adhesive bonding of a chip housing.
In a method for COB (Chip on Board) mounting, the electronic chips are fixed directly on a circuit board (PCB--Printed Circuit Board), subsequently contact-connected by bonding and finally enclosed by a covering compound. The COB method is used, inter alia, in the mounting of memory modules (SIMM, DIMM, etc.). In that case, generally two or more individual chips are mounted on a circuit board.
The method has the advantage of obviating following steps that are usually required, namely the mounting of chips which have already been provided with housings on the circuit board and the soldering of connections. However, the consequence thereof is that, in contrast to the conventional component-mounting methods, the chips can only be tested, or written to in the case of memory modules, in the completely mounted state. If such a chip is defective or fails, which is often not noticed until after an artificial aging process (so-called burn-in process), it is generally very difficult and costly to remove that chip again from the circuit board and replace it with a new specimen. Moreover, the circuit board and, in particular, the conductor tracks can be damaged as a result.